Liquid-fuel burner



Nov. 17, 1 25; 1,561,474

I. E. MCCABE LIQUID FUEL BURNER Filed April 5. i924 3 Sheets- Sheet 1 vINVENTOR. F/g] 59M 6. MM

BY f m A TTORNEYS.

Nov. 17, 1925'. I 156L474 l. E. MCCABE LIQUID FUEL BURNER Filed April 3.1924 3 Sheets-Sheet 2 Z, i nu ullllll INVENTOR A TTORNEYS.

Nov. 17, 1925. 1,561,474

I. E. MCCABE LIQUID F EL BURNER 7 Filed April 5, 1924 3 Sheets-SheetINVENTOR. 2 a MOW A TTORNEYS.

Patented Nova 11?, 1925.

V UNITED STATES IRA E. means, or orzr'caeo, rumors.

LIQUID-FUEL BURN application filed April 3, 1924. Serial No. 703,8e1.

To all whom it may concern:

Be it known that I, IRA E. MCCABE, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Liquid-Fuel Burners, of whichthe following is a specification.

This invention relates to improvements in liquid fuel burners and moreparticularly to a mechanical safety control therefor.

Liquid fuel burners are replacing to a large degree the'burning -ofsolid fuel in furnaces of all characters, especially in furnaces for theheatin of dwellings and other buildings, being adapted to hot air, hotwater or steam heating systems. The most practical and commerciallysuccessful heating systems of this kind utilizing liquid fuel burners atthe present time include electrically operated means actuating theburner with a thermostatic control therefor to maintain the desiredtemperature in the building to be heated. It is not only desirable butusually required by fire regulations that burners of such systems usedin means to cutoff the supply of liquid fuel should, from any cause, theburner fail to ignite, the flame become extinguished or in the eventthat unconsumed fuel flood the combustion chamber. 7

Heretofore the conventional means generally employed as a safety devicefor this purpose depended upon the weight of oil accumulated from theextinguished burner o close the oil supply valve or break the electriccircuit or both, the accumulation being depending upon accomplished in afixed receptacle which operated a float therein connected to theoperating member of the valve or electric switch or in a movablereceptacle. such a aeup, operated by the weightof the liquid accumulatedtherein to act directly upon the operating member of the valve or switchthe ability of the receptacle to positively contain the liquid as itaccumulated therein before functioning.

It is an object of this invention to provide a mechanical safety'deviceof this general character actuated by a flow of oil from theextinguished burner or from the combustion chamber that will functionwith a minimum volumne of the liquid therefrom, will act ndependentlywithoutretaining the flowing type of liquid provided with mechanicalliquid and, in the case of a float operated device, without the buoyancyof the float remaining constant.

With this and other objects in view reference is made to theaccompanying sheets of drawing illustrating a preferred form of thisinvention as applied to a conventional fuel burner system for heatmgpurposes. It being understood that this device is adaptable to othertypes of such system, as well as other types of liquid fuel burners forother purposes and what minor changes may be made therein withoutdeparting from the scope of this invention.

In the drawings: a

Figure l is diagrammatical view of an oil burning heating system withthe controls therefor.

Figure 2 is .an enlarged detail view of a float operated safety'deviceembodying this invention, partly in section.

Figure 3 is a similar view of another form of counter weight operatedswitch.

Figure 4 is a similar view of another form of float operated switch.

Figure 5 is a detail view of a four terminal switch tube which may beused in connection with the safety control.

To'illustrate an embodiment of this invention an oil burning heatingunit and controls is graphically shown in Figure 1, in which the furnace1 contains a combustion chamber 2 having an air conduit v8i leadingtherefrom to an electric motor 4 driving a blower fan with an oil pipeleading from a tank or other source of supply through an oil pump drivenby the motor a or by gravity to an oil burner at the entrance of the airconduit with the combustion chamthe cial power line of. which lead Apasses through one or more thermostatic switches 5 placed in the room orrooms to be heated, through a' furnace control switch 6 thence through amechanicallyv operated safety switch 7 to one poleof the motor 4 whilethe lead B passes'directly to the opposite 018 of the motor, both leadspassing 'filed Oct. 23, 1922, respectively.

through a hand thrown switch 8. While the control switches 5, 6 and 7may be of any known type to perform the functions designated, it ispreferable to use mercury tube snap switches such as are illustrated uon these drawings and which are fully descri 'ed in my prior pendingapplications 535,755 filed Feb. 11, 1922; 538,916 filed Feb. 24, 1922;585,698 filed Sept. 1, 1922; and 596,408

' within the switch casing and extending therebeyond with a link 10connecting the lever arm to the snap movement of the switch so thatmovement up and down of the free end of the lever 'will throw the switchto break and make the circuit. The safet switch may be of the type shownor may he provided with a four terminal switch tube shown in Figure 5 inwhich two of the terminals may be connected to a bell circuit so thatwhen the motor circuit is broken the bell circuit will be closed to actas an alarm when the-motor is cut off or the terminals may be soconnected in a relaycircuit sothat when the, current passing through thesafety switch normally is insuflicient to cut out the motor or operate avalve the operation may be accomplished by the relay circuit.

In the form shown in Figure 1 a drain pipe 11 is provided leading fromthe bottom of the combustion chamber 2 so arranged that should the oilfrom the source be supplied and the burner fail to i nite, beextinguished or the chamber be ooded from any cause, the oil accumulatedtherein will lead through the drain pipe to a mechanical safety devicethat will actuatethe operating lever 9 to throw the safety switch tobreak the circuit. This actuating means comprises a receptacle 12carried upon the free end of the operating lever and preferably rigidlysecured thereto. This receptacle is provided with a siphon 13, shown indotted lines so arranged that as the oil from the drain pipe 11 causesthe level of the oil in the receptacle to rise above the upper bend inthe siphon, the siphon will operate to empty the receptacle. Theoperating 1ever9 is connected to a counter weight 14, by a link 15, ofsufficient size to raise. the empty rece tacle and operating lever tothe position s own in dotted lines nd thereby throw "he snap switch tobreak the circuit. To close the circuit a sufficient amount of oil orany other liquid is poured into the receptacle 12 to to start thesiphon, and cause the receptacle and likewise the lever 9 to assume itslowermost sition, throwing the sna switch to close t e circuit. The openend 0 the siphon 13 within the receptacle is preferably arranged nearthe bottom of the receptacle with the bend below the top thereof. It ispreferable to rovide a drippan 16 in the floor below t e exterioropening of the siphon of suflicient size to catch the liquid dlschargetherefrom which pan may ifdesired, be connected to a drain in the floorleading to the sewer. The discharge end of the combustion chamber drainis so arranged in relation to the receptacle that it will be cleared asthe receptacle is emptied and swings upward by the influence of thecounterweight in which position it will re-' main until manually movedto its lower position and sufficiently filled to remain there, in themeantime any further discharge from the oil drain 11 will be caught inthe pan 16.

The siphon 13 must be of greater discharge capacity than the dischargeof the drain pipe 11 to function and reduce the level of the liquid inthe receptacle. A

overcome the counter weight, but insufiicient safety device of thischaracter has a wide range of operativeness depending upon the level ofthe liquid contained therein when placed in operative position. Thesensitiveness increases as the level approaches the top of the bend inthe siphon, it may be initially set to operate only after a considerableoil has flowed from the combustion chamber to such a nicety that theflow of a single teaspoon from the combustion chamber will operate thesiphon and thereby the switch, the flow beyond that point beingimmaterial as the siphon dischar es more rapidly than the drain pipefrom t e chamber and as the discharging receptacle is moved from underthe drain pipe all excess discharge therefrom is caught in the pan 16.Furthermore should the receptacle become damaged and leak, while the oilat the burner is in flame and operating, as soon as the receptacle isdrained to a point to become possibly imperative the counter weight willoperate the safety switch to break the circuit, thereby forming anadditional safety device for the burner.

From this illustration and descriptionit is readily seen that theoperation of this safety device depends upon a fiow of oil from thecombustion chamber and isindependent of the amount or duration of suchflow the quantity required to operate it depending upon the nicety ofwhich it is originally placed in operatlveposition and further theevaporation or leakage of the liquid holding it in operative positionwill cause l*ig1l1'c 1 will shut off the burner.

In case it is desirable to employ a float operated switch a stationaryreceptacle 20 is provided, see Figure 2, which may rest upon the floorwith a combustion drain pipe 21 leading directly into the top of thereceptacle and a siphon 22 arranged exteriorly thereof leading from thebottom of the receptacle and discharging into a drain 23 in the floorleading to the sewer, with the siphon discharging more rapidly than the.

drain pipe 21 and the top bend of the siphon below the entrance of thesaid drain pipe into the receptacle. A float 2% is arranged within thereceptacle which will rise and fall with the level of the liquidcontained in the receptacle and is provided with a stem 25 which may beconnected to the free end of an operating lever such as lever 9 abovedescribed with the mercury tube reversed as shown in Figure l or to avalve 26, as hereinafter described. In either casesufficient liquid ofany kind is placed in the receptacle, preferably by pouring on thisfunnel like closure 27 of the top thereof, to raise the floatsufiici'ently to close the circuit or open the valve to operate theburner.

Upon flow of'oil from the combustion chamher through the drain pipe 21into the receptacle the level of the liquid therein will rise until itreaches the top of the bend in the siphon, as indicated by the dot anddash line, Figure 2, when the siphon will discharge and. lower theliquid to the level as shown, the weight of the float arranged to besufficient on its descent to throw the switch or close the valve. Thenormal operative position of the float being supported in the liquid ofa level between that which will close the circuit or open the valve andthe level of thedot and dash line.

The construction shown in detail in Figure 2 is a float operated valvein the supply pipe 28 leading from a source of oil on the left, notshown, to the burner on the right, not shown, in which the valve head 26carried on the end of the float stem 25 is arranged to be raised abovethe seat 29 in the valve so interposed in the oil line by the float whenin normal operative position and to be closed upon said seat and cut offthe' oil supply to the burner when the float is lowered by the dischargeof liquid from the receptacle caused by a flow of oil from thecombustion chamber.

It may be desirable to provide an intermittently operating safetydevice, especially where an electric ignition system for the burner isemployed and when the spark therefrom does not ignite the oil at theburner initially, or when the combustion chamber is cold. i

A device of this character is shown in snap switch construction of thesame type as shown in Figure 1 with a counter weight 32 arranged on thelever at the other side of the pivot and within the casing. This leveris preferably connected to the snap mechanism of the switch by an arm 33extending from the lever between the counter weight 32 and pivot havingan undulating surface on one side thereof coacting with aroller mountedon one end of a member 34E pivotally carried on-the snap movementwith acounter weight on the other side thereof causing the member to maintaincontact with said undulating surface of arm 33 which forms a shoulder011 both sides of said roller when the snap movement'has been thrown ineither direction, the counter weight 32 and the depression of the'freeend of the lever 31 carrying the roller to first impart the adjacentshoulders.

The snap switch being in circuit with movement to the snap mechanism themotor, as shown in Figure 1, and initially filled with sufficient liquidto depress the lever 31 to close the circuit, and the spark of theelectric ignition fails to initially ignite the oil at the burner, theunconsumed oil will ow from the combustion chamber through drain pipe 35into the receptacle causing the level of the liquid to rise untildischarged from the receptacle by I the siphon 36. The counter weight 32will then throw the switch to break the circuit and cut off the motor,however, the receptacle in this case is pivoted to this lever 31, sothat in its upward movement the receptacle still remains under thedischarge end of the drain pipe 35 so that if the oil still flows fromthe combustion chamber, after the motor is cut off and the receptaclesiphoned ofi', it will upon the failure of the siphon again raise thelevel of the liquid in the receptacle which will, if the oil continuesto drain, overcome the counter weight 32 to close the circuit to allowthe spark of the agnition system further time to ignite the oil at theburner and then operate as at first described should the burner fail tobe ignited or later become extinguished. Inthis case the pan 37 isarranged below the receptacle to receive the oil discharged from thesiphon.

At times it may safety same time the supply of oil to the burner orthesupply of oil or gas to a pilot light for the burner independent of themotor. Such a device is shown in Figure 4 and com= be desirable toprovide a prises a float operated arrangement similar to that; shown inFigure 2 with the stem 25 of the float pivotally attached to the deviceto cut off the motor and at thefreeends of o crating levers 40 and 41.

I Lever 40"exten s from the casing 42 or a mercury tube snap switch incircuit with the motor, is pivoted therein and connected by a link 43 tothe snapmovement, the mercufigtube so arranged that the circuit isclosed upo the upward movement of the lever 40 and opened upon thedownward movement thereof. Lever 41 enters into a valve casing 44interposed in the oil line 45 to the burner or gas or oil line'to thepilot light for the burner, as the case may be, with the gas or oilflowing from left to right throughlthe valve casing. The valve head 46is provided with a sliding connection with the interior end of the lever41 so as to be. unseated and open upon the upward movement of theexterior end and close and seated upon the downward movement thereof.

In this figure the float 24 is shown in the operative, position with theexterior ends of levers 40 and 41 in raiseil positions closing thecircuit through the snapswitch to the motor and opening the oil or gaspipe to the burner or pilot light, liquid havin been introduced, to thelevel shown, int c receptacle. Upon failure of the burner flame.

from any cause or upon the flooding of the combustion chamber theunconsumed oil will flow from the chamber through the drain pipe 21 intothe receptacle 20 until its level therein is above the top of the bendin the siphon 22 which will then operate to discharge into drain 23until the level is reduced to the end of the siphon. near the bottom ofthe receptacle causing the float to move downward with the liquid movingthe exterior ends of thelever 40 and 41 at the same time to break thecircuit of the motor and close the oil or gas valve in unison. In

. this form the drain .pi e 21 is shown discharging into the funne sha.ed cover 27 of the. receptacle and asses t rough the en-- larged openingfor t e valve stem.

In these float operated devices shown in Figures 2 and 4 the movement ofthe floats is limited by the bottom of the float resting upon the bottomof the receptacle in its. downward movement and the top of the floatengaging the under side of the funnel shaped top cover 27 The normaloperative position of the float is reached by pouring liquid into thereceptacle until the, top of the float contacts with the top float 27which can be observed through the opening therein of the-float stem .orthrough apertures provided-for that purpose. If there is any .buo anc atall in the float it will operate.

If t e float has been damaged or leaks until it becomes water logged itwill not rise when liquid is poured into the receptacle and such ,placedin operative position.

In case the float is arranged to control the operation of a pilot lightfor the burner it may also operate a means for diverting further flow ofunconsumed oil from the combustion chamber to the floor drain after thepilot light valve has once been closed to prevent its operatingintermittently.

' To insure the positive operation of the siphon it is preferable,particularly in siphons of large diameter, to provide a liquid seal atthe discharge end either in the form of the cup 47, as illustrated inthe drawing,

or by bending the discharge end upward in what is known as a goose neck48, as shown in Figure 3, whereby suflicient liquid is retained in thesiphon tube to form a seal for that end. As illustrated a cup orreceptacle 47 is attached to the discharge end of the siphon 13extending upwardly and thereabout to form a seal confining the air inthe tube 13, allowing only the excess pressure to escape as the level ofthe liquid in the siphon connected receptacle rises, so that when thelevel has reached a point above the bend the liquid therein willpositively siphon out.

What I claim is: v

1. In a liquid fuel burning furnace including an electric circuitoperating a motor supplying fuel to the furnace and having a roomthermostat and .furnace control switches in circuit therewith, a burnerdirecting its flame into a combustion chamber within the furnace, adrain pipe for leading the unconsumed fuel from said chamber, and asafety control switch inthe said circuit in combination with a liquidcontaining receptacle normally maintaining the safety switch in closedposition when partially filled and into which the drain pipe discharges,means in connection therewith operated by a flow of liquidfuel from thedrain pipe to empty the receptacle, and means operable when thereceptacle is empty to open said safety switch and thereby cut off thesupply of fuel to said burner.

2. In aliquid fuel burning furnace including an electric circuitoperating amotor supplying fuel to a burner directingits flame into acombustion chamber within the furnace with room thermostatic and furnacecontrol switches in circuit therewith, a drain pipe leading unconsumedli uid fuel from the combustion chamber, and a safety control switch insaid circuit in combination with a liquid containing receptaclemaintaining the safety switchin closed position and into which the fueldrain pipe discharges, a siphon in connection with the said receptacloperated by a flow of liquid from the drain pipe, and means for throwingthe safety switch when the receptacle is empty to break the circuit andthereby cut off the supply of liquid fuel to the burner.

plying fuel to the furnace and a drain pipe leading the unconsumed fuelfrom the furnace, a safety switch in circuit with the mo- I draindischarging into said receptacle, and

means therein operated by a flow of liquid from the drain tonlessen theweight thereof to allow the safety switch to be thrown into its normalopen position and thereby break the motor circuit and cut off the-supplyof fuel to the burner.

4. In a liquid fuel burning system for furnaces having an electric motorfor supplying fuelto the furnace, a drain for unconsumed fuel leadingtherefrom, a thermo-' drain to empty the receptacle, and meansassociated with the switch to allow the switch to be closed when thereceptacle is partially filled and to open the switch when therecepta'cle is empty. a

7. In a liquid fuel burning system for furnaces having an electric motorfor supplying fuel to the furnace and a drain for leading unconsumedfuel from the furnace, a thermostatic switch controlling the operationof the motor, and a safety switch in circuit with the motor, a liquidreceptacle arranged to receive the discharge from the drain, a siphonadapted to be operated by a flow of liquid from the drain to empty thereceptacle, and means associated with the switch to allow the switch tobe closed when, the receptacle is partially filled and static switchcontrolling the operating oft to open the switch when the receptacle isthe motor, and a safety switch in cireiiit with the motor having meansarranged to throw the switch to the open position" and a weighted meansnormally acting in opposition thereto to close the switch associatedwith means lessening the weight of said means operated by a flow ofliquid from said drain allowing the safety switch to be opened by thefirst means andthereby cut off the supply of fuel to the furnace.

5. In a liquid fuel burning system for furnaces having an; electricmotor for supplying fuel to the furnace, a drain leading unconsumed fuelfrom the furnace, a furnace control switch in circuit with the motor.

and a safety switch insaid circuit having means arranged to open theswitch, and a weighted means in opposition thereto to close the switchcoacting with a flow of liquid from the drain to lessen the weight ofsaid opposing means and allow the switch to be opened by the first meansand thereby cut ed the supply of fuel to the furnace.

6; In a liquid fuel burning system for furnaces having an electric motorfor supplying fuel to the, furnace ,and a drain for leading unconsumedfuel from the furnace, a safety switch in circuit with the motor. a

a liquid receptacle arranged to receive the discharge from the drain, asiphon adapted to be operated by a flow of liquid from the p y- 8.111 aliquid fuel burning system. for furnaces having an electric motorforsupplying fuel to the furnace and a drain for leading unconsumed fuelfrom the furnace, ",a' furnace control switch in circuit with the motor,and a safety switch in said vcircuit, a liquid receptacle arranged toreceive the. discharge from the drain, a siphon adapted to be operatedby a flow of liquid from the drain. and means associated with the switchto allow the switch to be closed when the receptacle is partially filledand toopen the switch when the receptacle is empty.

' 9. A. safety device for oil burning systems having aisupplv of oil toa burner and a drain for leading unconsumed oil therefrom, comprising areceptaclenormally partiltv tially filled with liquid arranged toreceive the discharge from the drain, a siphon in the receptacle. 4

3 IRA McOABE.

